Method and apparatus for cleaning mounting nozzle, and mounting machine

ABSTRACT

A cleaning apparatus according to the invention is used for an electronic component mounting machine, includes a abrading unit for abrading the suction surface of the mounting nozzle; and a drive unit for moving the abrading unit in a predetermined direction, the abrading unit being formed by a ceramics structure, and a grain size of a contact surface of the abrading unit ranges from P1000 to P5000, the contact surface of the abrading unit coming into contact with the suction surface of the mounting nozzle.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method and an apparatus for cleaning a mounting nozzle included in a mounting machine which mounts electronic components and the like on a substrate and the like, and the mounting machine into which the cleaning apparatus is incorporated.

2. Related Background Art

Conventionally an electronic component mounting machine for placing the electronic components, such as flip chip cut from a wafer, on a circuit board and the like is used. Generally the electronic component mounting machine includes a pick-up unit and a mounting unit. The pick-up unit picks up the chip from the wafer to transport the chip to the mounting unit, and the mounting unit places the chip delivered from the pick-up unit on the circuit board and the like.

In the electronic component mounting machine, by using a suction nozzle communicated with a vacuum source, the chip is picked up from the wafer and the chip is mounted onto the circuit board. Accordingly, it is not desirable that swarf, dust, wafer paste, and the like exist on a suction surface of the suction nozzle, because there is a fear that the swarf, the dust, the wafer paste, and the like obstruct suction and hold of the chip. Therefore, conventionally the swarf, the dust, and the wafer paste which adhere to the suction surface are removed by an abrasive member, a brush, and the like.

FIG. 4 is a perspective view showing a part of a conventional electronic component mounting machine. A mounting unit 801 includes a base 811 and a mounting nozzle main body 809. The base 811 extends in an x-axis direction, and the mounting nozzle main body 809 is attached to the base 811 while being movable in the x-axis direction. The mounting nozzle main body 809 includes a suction nozzle 813 whose suction surface is faced downward.

A cleaning unit 815 is arranged below the mounting unit 801. The cleaning unit 815 includes a y-axis base 807 and an abrading stage 805. The y-axis base 807 extends in a y-axis direction, and the abrading stage 805 can be moved on an upper surface of the y-axis base 807 in the y-axis direction. An abrasive member 803 is arranged on the upper surface of the abrading stage 805.

In the electronic component mounting machine having the above configuration, the suction nozzle 813 is caused to fall so as to come into contact with the abrasive member 803. Then, while the mounting nozzle main body 809 is moved in the x-axis direction, the abrading stage 805 is moved in the y-axis direction. Therefore, the cleaning is performed by abrading the suction surface (contact surface with the chip) of the suction nozzle 813 (for example, see Japanese Patent Application Laid-Open No. 2002-313837).

FIG. 5 is a perspective view showing a part of another conventional electronic component mounting machine. The mounting unit and the cleaning unit of the mounting machine are schematically shown in FIG. 5. A mounting unit 903 includes an x-axis base 905, a y-axis base 907, a nozzle support unit 909, and a suction nozzle 911. The y-axis base 907 is attached onto a lower portion of the x-axis base 905. The nozzle support unit 909 is attached to the x-axis base 905. The suction nozzle 911 extends downward from the nozzle support unit 909, and the suction nozzle 911 can be lifted up and down. A cleaning unit 951 includes a moving stage 953, a grindstone member 955, a rotating brush 957, and a drive member 959. The moving stage 953 is movable both in the x-axis direction and in the y-axis direction. The grindstone member 955 is arranged on the moving stage 953. The drive member 959 rotates the rotating brush 957.

In the above configuration, a suction surface 913 of the suction nozzle 911 is moved onto the grindstone member 955 of the cleaning unit 951, and the suction surface 913 is cleaned by rubbing the suction surface 913 with the grindstone member 955. Further, the suction nozzle 911 is moved to a position where the dust and the like on the suction surface 913 can be removed with the brush of the rotating brush 957, and the cleaning is performed with the rotating brush 957 (for example, see Japanese Patent Application Laid-Open No. 10-64958).

In order to maintain the suction surface of the mounting nozzle in a good state to securely suck and hold the electronic component, in the cleaning apparatus which cleans the suction surface, frequency of the cleaning operation is increased. For example, in order to remove the paste of a dicing tape, the dust, and the like which adhere to the suction surface of the mounting nozzle, the cleaning is performed at each time in which the mounting of one electronic component is ended.

When the abrasive member generally used (for example, a rubbing film which is coated with diamond, chromium oxide, iron oxide, and the like) is utilized, sometimes grains are peeled off from the abrasive member, or sometimes the peeled grains adhere to the suction surface of the mounting nozzle. When the grains are peeled off from the abrasive member, because the suction surface cannot be abraded with a predetermined grain size, there is a fear that the cleaning is not sufficiently performed. In the state in which the peeled grains adheres to the suction surface, the mounting nozzle fails to suck the electronic component, the surface of the electronic component is damaged by the grains on the suction surface, or sometimes the electronic component is broken by the grains.

Further, with the miniaturization and thickness reduction of the recent electronic component, it is necessary to strictly control surface roughness of the suction surface of the mounting nozzle when the electronic component is sucked and held.

SUMMARY OF THE INVENTION

An object of the invention is to provide a cleaning apparatus including the abrasive member in which the peel of the abrasive grain is not generated when the suction surface of the mounting nozzle is cleaned. The abrasive member can control the surface roughness of the suction surface at high accuracy. In the abrasive member, the dust and the swarf do not affect the suction surface which is of an abrading target, and the paste of the wafer does not adhere to the suction surface. Another object of the invention is to provide a mounting machine which can stably mount the electronic component onto the circuit board.

In order to solve the above problems, one aspect of a cleaning apparatus of the invention which is used for an electronic component mounting machine, the electronic component mounting machine including a mounting nozzle for mounting an electronic component on a circuit board, a suction surface which sucks and holds the electronic component being provided at a leading end portion of the mounting nozzle, the cleaning apparatus including abrading means for abrading the suction surface of the mounting nozzle; and drive means for moving the abrading means in a predetermined direction, wherein the abrading means is formed by a ceramics structure, and a grain size of a contact surface of the abrading means ranges from P1000 to P5000, the contact surface of the abrading means coming into contact with the suction surface of the mounting nozzle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a mounting machine to which a cleaning apparatus of the invention is applied;

FIG. 2 is a perspective view showing a main part of the cleaning apparatus;

FIG. 3 is a graph showing surface roughness of a suction surface in which cleaning has been performed with the cleaning apparatus of the invention;

FIG. 4 is a perspective view showing the main part of the mounting machine to which a conventional cleaning apparatus is applied; and

FIG. 5 is a perspective view showing the main part of the mounting machine to which another conventional cleaning apparatus is applied.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the specification, the mounting nozzle shall mean a member which sucks and holds a working object by drawing a vacuum through a suction port communicated with a vacuum source, and the mounting nozzle shall include a pick-up nozzle used in the pick-up unit and a mounting nozzle used in the mounting unit.

Further, a grain size used in the specification shall be described by a numerical value pursuant to JIS (Japanese Industrial Standard) R 6010: 2000 which is pursuant to ISO (International Standards Organization) 6344-1: 1998.

Referring to the drawings, preferred embodiments of an electronic component mounting machine to which a cleaning apparatus of the invention is applied will be described in detail below.

FIG. 1 is a perspective view showing the whole of the electronic component mounting machine. An electronic component mounting machine 101 includes a component pick-up unit 201, a mounting unit 301, a cleaning unit 501, and a circuit board feeding unit 401. The component pick-up unit 201 picks up the individual chip (electronic component) which is formed by cutting a substantially circular wafer. The mounting unit 301 receives the chip from the component pick-up unit 201 to mount the chip on the circuit board. The cleaning unit 501 cleans the suction surface of a mounting nozzle 309 in the mounting unit 301. The circuit board feeding unit 401 supplies the circuit board on which the chip is mounted.

The component pick-up unit 201 includes a first base 203, a component feeding table 217, a drive unit 207, and a position recognition camera 209. A pick-up nozzle 213 which sucks and holds the individual chip is movably arranged in the first base 203. The component feeding table 217 extends toward a direction crossing a longitudinal direction of the first base 203. The drive unit 207 moves the pick-up nozzle 213 in an x-axis direction 215, a rotating direction 219, and the like. The position recognition camera 209 recognizes a position of the chip.

A wafer table 205 is arranged on the component feeding table 217. The wafer (not shown) is arranged on the wafer table 205. A push-up pin (not shown) is arranged on the lower side of the wafer table 205, and the push-up pin pushes up a predetermined chip from the lower side so that the pick-up nozzle can suck and hold the predetermined chip.

The mounting unit 301 includes a second base 313, a mounting unit 303, and drive units 305 and 315. The second base 313 extends toward a vertical direction with respect to the longitudinal direction of the first base 203 of the component pick-up unit 201. The mounting unit 303 is movable along the second base 313, and the mounting unit 303 includes a mounting nozzle 309. The drive units 305 and 315 move the mounting nozzle 309 in a vertical direction and in a y-direction 311.

The circuit board feeding unit 401 feeds a circuit board 407 onto which the chip is placed. The circuit board feeding unit 401 includes an x-axis base substrate 403, a y-axis base substrate 405, and a circuit board holder 409. The x-axis base substrate 403 includes an x-axis table 404 which is movable in an x-axis direction 411. The y-axis base substrate 405 is installed on the x-axis table 404, and the y-axis base substrate 405 includes a y-axis table 406 which is movable in a y-axis direction 413. The circuit board holder 409 is installed on the y-axis table 406. The circuit boards 407 are loaded in the circuit board holder 409.

The x-axis base substrate 403 and the y-axis base substrate 405 are coupled to an x-axis drive motor 415 and a y-axis drive motor 417 respectively. The circuit board holder 409 is moved in the x-axis direction 415 such that the y-axis base substrate 405 installed on the x-axis table 404 is moved by driving the x-axis drive motor 415. The circuit board holder 409 is moved in the y-axis direction 413 such that the y-axis table 406 is driven by the y-axis drive motor 417.

Then, the cleaning unit which cleans the mounting muzzle 309 of the mounting unit 301 will be described. The cleaning unit 501 is provided in the second base 313. The cleaning unit 501 includes a cleaning unit main body portion 503 and an abrading stage 513. The cleaning unit main body portion 503 is attached to one side face of the second base 313. The abrading stage 513 is arranged on an upper surface of the cleaning unit main body portion 503.

Referring to FIG. 2, the cleaning unit 501 will further be described below. FIG. 2 is a perspective view showing a main part of the cleaning unit. The abrading stage 513, which is movable in x-directions 511 and 519, is provided on the upper surface of the cleaning unit main body portion 503. Drive means for moving the abrading stage 513 in the x-axis direction is provided in the cleaning unit main body portion 503, and the drive means includes a drive motor 521 and a ball screw (not shown). An abrasive member 505 is installed on the abrading stage 513.

In the abrading stage 513, L-shaped clips 515 and 517 are provided on both end faces which are faced to each other in the x-direction respectively. The both end faces of the abrasive member 505 are fixed to the abrading stage 513 by the clips 515 and 517. Therefore, the attachment of the abrasive member 505 to the abrading stage 513 and the detachment of the abrasive member 505 from the abrading stage 513 can easily be performed. Accordingly, a time required to change the abrasive members can be shortened, even if the abrasive member 505 is changed according to the change of the mounting nozzles or the change in surface roughness of the chip.

Referring to FIG. 1, a process of taking out the chip from the wafer to mount the chip on the circuit board with the mounting machine 101 will be described below.

After the position of the chip which is of the mounting object is confirmed with the position recognition camera 209, the pick-up nozzle 213 is moved to a predetermined position on the wafer table 205. The predetermined chip is lifted by elevating the push-up pin located on the lower side of the wafer table 205. The predetermined chip is sucked and held while faced downward by running suction means (not shown) communicated with a suction hole of a suction surface in the pick-up nozzle 213.

The, the chip is faced upward by reversing the pick-up nozzle 213 (direction of an arrow 219). The pick-up nozzle 213 holding the chip is moved to a position where the chip is delivered to the mounting unit 301 by the drive unit 207. On the other hand, the mounting nozzle 309 is moved to the delivery position of the chip by the drive units 305 and 313.

At the delivery position, the suction surface of the mounting nozzle 309 comes into contact with the chip from above the chip and the suction surface of the pick-up nozzle 213 comes into contact with the chip from under the chip. At this point, while suction force of the pick-up nozzle 213 is released, the suction force is generated by running suction means (not shown) communicated with the mounting nozzle 309. Therefore, the chip is sucked and held by the mounting nozzle 309.

The mounting nozzle 309 moves the chip to the predetermined position, and the chip is fixed by an ultrasonic bonding and the like to a predetermined point of the circuit board 407 which is taken out from the circuit board folder 409 by circuit board taking-out means (not shown).

Referring to FIG. 2, a process of cleaning a suction surface 309 a of the mounting nozzle 309 will be described below. The mounting nozzle 309 is caused to fall so that the suction surface 309 a of the mounting nozzle 309 comes into contact with the surface of the abrasive member 505. The mounting nozzle is caused to further fall so that the abrasive member 505 is pressed against the suction surface 309 a with predetermined pressure.

While the mounting nozzle 309 is reciprocally moved at a predetermined speed in the y-direction 311, the abrading stage 513 is reciprocally moved at a predetermined speed in the x-directions 511 and 519. Therefore, the abrasive member 505 is moved relative to the suction surface 309 a, which allows the suction surface 309 a to be cleaned. The abrading operation is performed while the suction surface is substantially parallel to the surface of the abrasive member. In FIG. 2, the suction nozzles shown by alternate long and two short dashes lines on both sides of the suction member 309 along the y-direction 311 are the suction nozzles moved in the y-direction. Similarly the state in which the abrading stage 513 is moved in the x-axis direction 519 is shown by the alternate long and two short dashes lines.

In the embodiment, the mounting nozzle 309 is moved in the y-directions 311 and 313, and the abrading stage 513 is moved in the x-directions 511 and 519. However, the invention is not limited to the embodiment. That is, it is possible that the abrading is performed in the state in which the movement of the abrading stage 513 is stopped while the mounting nozzle 309 is moved in the x-directions 511 and 519 and in the y-direction 311. Further, it is also possible to stop the movement of the mounting nozzle 309 while the abrading stage 413 is moved in the x-directions 511 and 519 and in the y-direction 311.

In the embodiment, the cleaning apparatus cleans (abrades) the suction surface of the mounting nozzle. However, needless to say, the cleaning apparatus can also be utilized for the cleaning of the pick-up nozzle. Further, the cleaning apparatus of the invention can be applied to the means for cleaning the suction surfaces of mechanisms which suck and hold the electronic component by the vacuum suction.

EXAMPLE

In the above configuration, the surface roughness of the suction surface of the mounting nozzle was compared using a ceramic structure as the abrasive member. The following table shows the result.

According to the findings of the inventors, it is found that the surface roughness of the suction surface of the mounting nozzle preferably ranges from P800 to P6000.

When the surface roughness of the suction surface is higher than P6000 (when the surface roughness of the suction surface becomes flatter), there is a fear that the chip falls down during the conveyance because friction is decreased between the suction surface and the chip. Further, the abrasive member having the grain size equal to or more than P6000 is required in order to obtain the surface roughness of the suction surface higher than P6000. In this case, due to the size of dust and the like generated during the cleaning, there is a fear that the dust exists on the surface of the abrasive member while the dust is not taken in the gap between the particles constituting the ceramic structure.

When the surface roughness of the suction surface is lower than P800 (when the surface roughness of the suction surface becomes rougher), there is a fear that the chip surface is damaged when the chip is sucked and the like. When projections and depressions become larger, because a contact area is not sufficiently secured between the chip surface and the suction surface, there is a fear that the chip falls down from the mounting nozzle during conveying the chip.

The abrasive member used in Example was alumina ceramics. The same effect as for alumina ceramics can also be expected when zirconia ceramics, silicon nitride ceramics, and silicon carbide ceramics are used. In Example, the alumina ceramics having the grain sizes of P1000, P5000, and P8000 were used as the abrasive member.

The mounting nozzle was made of stainless steel (SUS303). The suction surface of the mounting nozzle had a substantially square shape whose one side is 1 mm, and the suction hole whose diameter is about 0.5 mm was provided in the substantial center of the suction surface.

The pressing force of the mounting nozzle against the abrasive member was set at 3N. The inventors and the like obtain the findings that the pressing force preferably ranges from 0.5N to 20N. When the pressing forces larger than 20N are applied, there is a fear that the suction surface is deformed because an excessive load is applied to the suction surface of the abrasive member. When the pressing forces smaller than 0.5N are applied, there is a fear that the abrading is not sufficiently performed between the suction surface and the abrasive member.

It is best when the time required for the abrading becomes shorter. However, from the viewpoint of the actual process of mounting the electronic component, it is necessary to finish the cleaning process within 30 seconds.

Speed of the mounting nozzle relative to the abrasive member was set at 2 mm/s. According to the findings of the inventors and the like, it is found that the relative speed can appropriately be set in the range of 1 mm/s to 10 mm/s. In order to finish the cleaning process within a predetermined time, it is possible to appropriately change the relative speed according to the pressing force applied to the predetermined mounting nozzle. The suction surface was abraded by linearly reciprocally moving the abrading stage 513 in the x-directions 511 and 519 while the mounting nozzle was fixed.

FIG. 3 is a graph showing the surface roughness of the suction surface in which the cleaning has been performed on the above conditions. A horizontal axis is abrading time (second) and a vertical axis is abrading quality (surface roughness).

As can be seen from the graph of FIG. 3, when alumina ceramics having the grain size of P1000 is used, the surface roughness of the suction surface of the mounting nozzle exceeds P800 which is of the lower limit in about ten seconds, and the surface roughness reaches a steady-state value. When the ceramics structure having the grain size of P5000 is used, the surface roughness of the mounting nozzle reaches in a proximity of P5000 in about 30 seconds, and the surface roughness becomes the steady-state value. Accordingly, when alumina ceramics whose grain size ranges from P800 to P5000 is used, it is found that the cleaning is performed in the abrading time of about 30 seconds while the suction surface has the predetermined surface roughness.

On the contrary, when the ceramics structure having the grain size of P8000 is used, the surface roughness does not reach the steady-state value even if the abrading time exceeds 60 seconds from the cleaning start. However, the surface roughness of the suction surface exceeds P800 which is of the lower limit required for the abrading quality when the abrading time exceeds 30 seconds. Namely, when the abrading time is set at about 30 seconds, because a control mechanism which maintains the surface roughness of the suction surface constant becomes complicated, the ceramics structure having the grain size of P8000 is not suitable for the abrasive member.

Accordingly, the mounting nozzle whose suction surface has the predetermined surface roughness can be provided in a relatively short time by using ceramics structure whose grain size ranges from P800 to P5000 as the abrasive member of the cleaning apparatus. Further, because of the feature that the ceramics structure has hardness higher than that of the mounting nozzle, abrasive particles can be prevented from peeling off.

Even if the dust is generated in the ceramics structure during the abrading process, in the grain size in the above-mentioned range, the dust can be taken in the gap between the alumina particles constituting the abrasive member to suppress the amount of dust to a small extent.

As a result, the dust and the like can be prevented from adhering to the suction surface and ultrasonic bonding, which is of a post-process, of the electronic component can stably be performed onto the circuit board.

Many modifications of the invention can be made without departing from the essential characteristics of the invention. Therefore, needless to say, the above embodiment and example are described for only illustration purpose, and the invention is not limited to the above embodiment and example.

This application claims priority from Japanese Patent Applications No. 2004-159195 filed May 28, 2004 and No. 2005-148930 filed May 23, 2005, which are hereby incorporated by reference herein. 

1. A cleaning apparatus which is used for an electronic component mounting machine, the electronic component mounting machine including a mounting nozzle for mounting an electronic component on a circuit board, a suction surface which sucks and holds the electronic component being provided at a leading end portion of the mounting nozzle, the apparatus comprising: abrading means for rubbing the suction surface of the mounting nozzle; and drive means for moving the abrading means in a predetermined direction, wherein the abrading means is formed by a ceramics structure, and a grain size of a contact surface of the abrading means ranges from P1000 to P5000 (JIS R6010: 2000), the contact surface of the abrading means coming into contact with the suction surface of the mounting nozzle.
 2. A cleaning apparatus according to claim 1, wherein the ceramics structure is made of any one of alumina ceramics, zirconia ceramics, silicon nitride ceramics, and silicon carbide ceramics.
 3. An electronic component mounting machine comprising a cleaning apparatus according to claim
 1. 4. An electronic component mounting machine comprising a cleaning apparatus according to claim
 2. 5. A method for cleaning a mounting nozzle, which is used in order to suck and hold an electronic chip component when the electronic chip component is mounted on a circuit board and the like, the cleaning method comprising the steps of: pressing a suction surface of the mounting nozzle against an abrasive member including a ceramics structure whose grain size ranges from P1000 to P5000 (JIS R6010: 2000); and moving relatively the abrasive member in parallel with the suction surface to abrade the suction surface in a state where the suction surface is pressed against the abrasive member. 